January 12, 2012
Kepler Finds Two More Two-Sun Planets
Astronomers announced the findings of two new circumbinary planets, or worlds that orbit two different stars, during the American Astronomical Society (AAS) meeting in Austin, Texas on Wednesday.
The discovery, which was presented by San Diego State University (SDSU) Associate Professor Dr. William Welsh and published online in the journal Nature, used data from NASA's Kepler Mission to locate a pair of transiting circumbinary planet systems.The two worlds, which have been dubbed Kepler-34b and Kepler-35b, are both gaseous planets roughly the size of Saturn, each orbit a "binary star" -- in other words, a pair of stars that are gravitationally attracted and orbit one another -- according to an SDSU press release.
They join Kepler-16b, discovered in September of last year and nicknamed "Tatooine" due it its resemblance to the fictional "Star Wars" world, as the only circumbinary planets confirmed to exist.
However, according to the university's press release, Welsh and his colleagues believe that such planets "are not rare exceptions, but are in fact common with many millions existing in our Galaxy."
"We have long believed these kinds of planets to be possible, but they have been very difficult to detect for various technical reasons," University of Florida Associate Professor of Astronomy Eric B. Ford, a member of the 46-person research team, said in a statement.
"With the discoveries of Kepler-16b, 34b and 35b, the Kepler mission has shown that the galaxy abounds with millions of planets orbiting two stars," he added.
In another press release detailing the finding, officials at the Harvard-Smithsonian Center for Astrophysics reported that the two systems are located in the constellation Cygnus the Swan. Kepler-34b is located 4,900 light-years from Earth, and Kepler-35b is 5,400 light years away.
Kepler-34b completes an orbit around its two stars every 289 days, with each sun orbiting the other every four weeks. The stars around which Kepler 35-b orbit are slightly smaller than the sun, and it takes the planet 131 days to orbit the pair. Its two suns orbit each other every three weeks, they added.
"It was once believed that the environment around a pair of stars would be too chaotic for a circumbinary planet to form, but now that we have confirmed three such planets, we know that it is possible, if not probable, that there are at least millions in the Galaxy," Welsh said.
"Once again, we're seeing science fact catching up with science fiction," added co-author Josh Carter, a member of the Harvard-Smithsonian Center for Astrophysics. "The search is on for more circumbinary planets, and we hope to use Kepler for years to come."
Image 1: A New Class of Planetary Systems: This artistic rendition depicts the Kepler-35 planetary system. In the foreground, Kepler-35b, a Saturn-size world orbits its host stars every 131 days. Image credit: © Mark A. Garlick / space-art.co.uk [ Full size image here ]
Image 2: The Kepler-35 System: An artist's rendition of the Kepler-35 planetary system, in which a Saturn-size planet orbits a pair of stars.
Image credit: Lynette Cook / extrasolar.spaceart.org [ Full size image here ]
On the Net:
- Kepler Mission
- American Astronomical Society (AAS)
- San Diego State University (SDSU)
- University of Florida
- Harvard-Smithsonian Center for Astrophysics